Japanese Unexamined Patent Publication No. 2002-353471 discloses an SFP (Small Form factor Pluggable) optical transceiver defined in the MSA (Multi-Source Agreement) standard. This optical transceiver includes an optical module part, a connecting component, a circuit board, an outer case housing the optical module part, the connecting component and the circuit board and having a rectangular cross section, and a board supporting member fixed to a rear end of the outer case and supporting the circuit board. The optical module part includes a light emitting elements and a light receiving elements as optic/electric converting elements, and is connected with the circuit board using the connecting component. A part of the outer case and the board supporting member constitute a plug part which is plugged into a cage connector of a motherboard. The circuit board has a card edge connector part on the rear end side thereof, and the card edge connector part protrudes from the board supporting member toward the rear end side of the optical transceiver. When the plug part is plugged into the cage connector, the card edge connector part is electrically connected with a terminal inside the cage connector. This connection allows the light emitting elements and the light receiving elements to be electrically connected with an electric circuit on the motherboard side via a circuit formed on the circuit board.